A wide variety of electronic data storage methods and devices have been developed. For example, U.S. Pat. No. 7,586,828 issued to Ma describes a “Magnetic data storage system.” Data is written on a shape memory thin film in the non-ferromagnetic austenite state by pressing an atomic force microscopy (AFM) tip into the surface. The indentation induces the martensitic transformation from a non-ferromagnetic to a ferromagnetic phase. This method makes use of the phenomenon called “stress-induced martensite formation”. The information is binary: ferromagnetic/non-ferromagnetic.
Also, U.S. Pat. No. 6,084,849 issued to Durig describes “Shape memory alloy recording medium, storage devices based thereon, and method for using these storage devices.” Data is written on a (non-magnetic) shape memory thin film in its (non-ferromagnetic) martensite state by pressing an AFM tip into the surface. The indent is produced by twin-boundary motion. Reading is achieved by scanning a probe over the indent. Erasing is achieved by heating the material above the martensite temperature.
Despite the unique materials used in Ma, Durig, and other known art, significant limitations exist in the described materials' ability to meet the performance expectations for modern data storage methods and devices. Accordingly, advances in the technology are conceivable.